Process of manufacturing vegetable glue.



UNITED STATES PATENT @FFIQE.

VICTOR G. BLOEIDE, OF CATONSVILLE, MARYLAND.

PROCESS OF MANUFACTURING VEGETABLE GLUE.

No Drawing.

To all whom it may concern:

Be it known that I, VIo'roR Gr. Bnonnn, a citizen of the United States, residing at Catonsville, in the county of Baltimore and State of Maryland, have invented new and useful Improvements in Processes of Manufacturing Vegetable Glue, of which the following is a specification.

This invention relates to an improvement in the manufacture of the compositions known as vegetable glue, produced by the action of a caustic alkali upon starchy matter, and used as a substitute for animal glue in paper box manufacture, wood-veneer and panel making and as a sizing or stiffening agent in textile work. The basic process underlying these compositions is the action of a caustic alkali on amylaceous matter,

thereby producing a thick, rubbery and exceedingly adhesive compound which has been known and in use for half a century,

and minor modifications of which process have been the subjects of numerous patents both in Europe and the United States.

. .The objection to all of these compounds generally applied is their extremely caustic or alkaline property, which renders them unfit for many purposes for which they could otherwise be used to great advantage. An alkaline compound of this type destroys the color of white, as well as tinted papers, and in wood-veneer work stains mahogany and other woods to such an extent asto make its application very difficult and limited, and in some cases impossible.

In addition to the above defects these strongly alkaline compounds have a highly corrosive action upon the skin, and a rotting effect upon other substances with which they are brought in contact.

My invention relates to a new compound, which, while possessing all of the desirable properties of the alkaline vegetable glue, is neutral in re-action, and non-staining, and can therefore be used upon the most delicate material without damage.

It would naturally suggest itself to anyone possessing a knowledge of chemistry that if after re-acting upon the starch the caustic alkali contained in the compound referred to was neutralized with a vegetable or mineral Specification of Letters Patent. Patented June 18, 1918.

Application filed October 10, 1917. Serial No. 195,751.

not impossible, to homogeneously combine any additional water with the compound after the composition has been formed in addition to which mechanical difficulty, the neutralized compound soobtained becomes too thin and loses many of its valuable properties by reverting to a pulpy and insoluble condition with greatly reduced cohesive, as

well as adhesive, and spreading properties, and in fact becomes generally unfit or impaired for the purposes for which the alkaline or caustic compound is found useful.

'I- have discovered a process or method of treatment of these viscous alkaline bodies which produces a neutral compound, which possesses most, if not all, of the desirable properties. of the alkaline or caustic starch composition, and this new com-pound and process is the subject of this specification.

My new process consists in first cooking the starch with a caustic alkali in the usual manner, and when the desired combination has been obtained to neutralize the free alkali by injecting into the viscous mass of cooked material through a pipe having numerous fine perforations, (which pipe may either be placed permanently at the bottom of the cooking vessel or introduced from the top, upon completion of the boiling) a mineral, or vegetable,'acid in vapor or gaseous form or in combination with air.

Practically any acid of a volatile or gaseous character can besuccessfully used for this purpose.

If a mild alkalinity in the finished product is not objectionable carbonic acid alone may be used, thereby reducing the caustic alkali to a carbonate, or carrying the process to super-saturation an acid carbonate.

If on the other hand perfect neutrality, or even a slight acidity is desired in the finishe pressed air may be used, and as both of these agents act as a diluent Where a stronger acid is employed the neutralization may be regulated to any degree desired.

The apparatus required in the conduct of I my process is a very simple one, for instance,

if muriatic or acetic acid is to be used as a neutralizing agent I place these acids in a strong vessel capable of resisting or carrying the necessary pressure, and force the air or carbonic acid through the liquid and connecting the top of this acid container with the perforated pipe contained in the kettle or cooker. By turning on the compressed air or carbonic acid this is forced through the liquid, rises through it carrying more or less of the liquid acid entrained, which passing through the alkaline starch mixture rapidly neutralizes the alkali. Control is kept in the usual way by testing from time to time with litmus paper, or other delicate reagents, and stopping the process by simply turning on the air or compressed gas when the desired stageof neutralization has been reached.

In case of the use of the gaseous acid, such as carbonic or sulfurous, these may be blown direct into the alkaline compound by their own pressure either when in liquid form or generated for the purpose by any of the ordinary methods.

I have found in practice that a slow neutralization gives rather better results than a rapid one, also that the milder acids are as a rule more desirable than the stronger acids, but by the use of compressed air the latter can be reduced and controlled in their activity toany extent desired, the more air used the smaller the percentage of the acid carried over in a given time.

I have also found by practical experience that I can secure better results if the acid vapor used for neutralization is applied by a rapidly revolving perforated pipe, thereby breaking up the bubbles formed by the air or gaseous acid, and bringing same in more rapid and closer contact with the material to be neutralized.

As a typical example of a vegetable glue,.

glue, or adhesive, by

rea ers clots and lumps. To this mixture add 2% to 3 lbs. of 76% caustic soda previously dissolved in 50 lbs. of water. Add this caustic liquor to the starch composition in the kettle, and after thorough mixing apply steam to the jacket of the kettle, raising the temperature to, or near, the boiling point, and continuing the agitation until all of the starch has been converted into a clear viscous paste.

In some cases less water is used, and in others more, and the alkali can also be increased and decreased depending upon the character of the paste desired, the character of the starch used, and the urposes to which the material is to be app 'ed, but the example given above may be considered a fair example of, the product usedunder the name of vegetable glue.

In the process herein described I do not limit myself to any particular acid, or combination of acids, as any volatile acid manifestly can be used to accomplish the results desired, and there are certain advantages in the use of particular acids, for instance, where suifurous acid is used either alone or in combination there is a certain bleaching action exerted which quite materially reduces the color of the compound when completed, while'muriatic acid has the advantage of working more quickly and producing only common salt as a product of neutralization.

Neitherdo I limit myself to any particular form of apparatus in carrying out my process, as this may be greatly varied according to conditions and circumstances.

I am aware that the process for the production of alkaline vegetable glues by the action of caustic soda on amylaceous or starchy matter has been known for many years. I am also aware that the neutralization, or partial neutralization, of these alkaline starch derivatives by means of vege table or mineral acids in aqueous solution or liquid form is not novel, and I do not there- 1gore broadly claim either of these processes,

I claim:

1. The process of iroducing a vegetable rst acting upon starch with a caustic alkali and water until a clear, viscous, solution or paste is formed, then neutralizing, or partly neutralizin the alkali contained in the paste so pro need, by means of an acid gas, or va or, injected into the body of the material su stantially as set forth.

2. The process of producing a vegetable glue or adhesive by first acting upon starch with a caustic alkali and water until a clear, viscous solution or paste is formed, then neutralizing, or partly neutralizing the alkali in such paste by injecting into the body of the material a current of air carrying an acid gas or vapor, substantially as set kali in such paste by in'ecting into the body forth. of the material a com ination of acids in 3. The process of producing a vegetable gaseous or vapor form. glue or adhesive by first acting upon starch VICTOR G. BLOEDE. 5 with a caustic alkali and Water until a clear, Witnesses:

viscous solution or aste is formed then ELMEB-L. GREENSFELDER, neutralizing, or part y neutralizing tile 31- Wm. H. THOMAS, Jr. 

